Antedating of "Outside the Box"

The files of the forthcoming Yale Book of Modern Proverbs have this antedating of the phrase "outside the box" (OED 1975):
1971 Michael R. Notaro, Jr., “Management of Personnel: Organization Patterns and Techniques,” Data Management 9, no. 9 (Sep.) 77: “THINK OUTSIDE THE BOX [section subtitle, capitalization as shown] / If you have kept your thinking process operating inside the lines and boxes [of organization charts], then you are normal and average, for that is the way your thinking has been programmed.”
Fred Shapiro
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